computing a difference between a site file and a raster file

[KLENKUS1 at VAXC.STEVENS-TECH.EDU]

First, thanks for the information on r.mapcalc and r.patch.
I chose to go with r.mapcalc and it worked perfectly.  
I had an overlapping area of two maps from which I found
the median between the two and used r.mapcalc to get the
new map and combined it with the second map.


Heres the problem I have now:

1.  I generated a raster file from a site list.

2.  The raster file and the site file seem to have a
    variance.  I would like to find the difference
    between the site and raster file.  If this information
	can be graphically reference it would be fantastic!

If anyone has any information on this type of problem,
it would be appreciated.


Kym M. Lenkus
Davidson Laboratory

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